41. The air pressure at the foot of a hill is 760mm of mercury. The height of the hill is given as 1360m and the density
of mercury is 13600 kgm? Calculate the density of air.

Complete these sentences. if a roller coaster train has a potential energy of 1,500 j and a kinetic energy of 500 j as it starts to travel downhill, its total energy isj. once the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 j, and its potential energy decreases to j. when the train reaches the bottom of the track and is traveling along the ground, its kinetic energy isj.